Thread: Connection pooling
Hi, my database has to handle quickly several number of queries per second from numerous clients. Because of the waste of time for connection/disconnection, Im' looking for a connection pooling tool. Where can I find a such tool or can somebody send me one ? Many thanks in advance, Guillaume.
Hi, With Apache/mod_perl it is very simple to enable DB connection persistance. in your perl script : use vars qw($dbh); $dbh ||= DBI::connect($datasrc, $dbuser, $dbpwd); That create a persistance connection to your DB and you do not have to care about a pool of connection. Double pipe do all for you :-) But if you really want a pool just create an array of this kind of global var at startup and switch to any indices as you want. Don't forget to use Apache::DBI on top of DBI.pm. See mod_perl documentation for a complete setting. Hope this help. Regards, Guillaume Lémery wrote: > Hi, > > my database has to handle quickly several number of queries per second > from numerous clients. > Because of the waste of time for connection/disconnection, Im' looking > for a connection pooling tool. > > Where can I find a such tool or can somebody send me one ? > > Many thanks in advance, > > Guillaume.
Quoting Guillaume Lémery <glemery@comclick.com>: > Hi, > > my database has to handle quickly several number of queries per second > from numerous clients. > Because of the waste of time for connection/disconnection, Im' looking > for a connection pooling tool. > > Where can I find a such tool or can somebody send me one ? What interface are you using? JDBC/ODBC/LibPQ? Peter > > Many thanks in advance, > > Guillaume. > > -- Peter Mount peter@retep.org.uk PostgreSQL JDBC Driver: http://www.retep.org.uk/postgres/ RetepPDF PDF library for Java: http://www.retep.org.uk/pdf/
Gilles DAROLD writes: > With Apache/mod_perl it is very simple to enable DB connection > persistance. > > in your perl script : > > use vars qw($dbh); > > $dbh ||= DBI::connect($datasrc, $dbuser, $dbpwd); Even better, Apache::DBI will pool across Perl programs, and you don't have to change anything in your scripts.
On Thu, 25 Jan 2001, Gilles DAROLD wrote:
> Don't forget to use Apache::DBI on top of DBI.pm. See mod_perl
> documentation
> for a complete setting.
Apache::DBI is supposed to be supporting connection pooling in the near
future.
-- Brett
http://www.chapelperilous.net/~bmccoy/
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On Thu, Jan 25, 2001 at 01:12:48PM -0500, Brett W. McCoy wrote: > Apache::DBI is supposed to be supporting connection pooling in the near > future. I believe this is scheduled (and only technically possible) with mod_perl 2.0, which will work with Apache 2.0 -- and they're both still in alpha. So I wouldn't hold your breath... But I agree -- mod_perl 2.0 will be really good, when it's released. -- Neil Conway <neilconway@home.com> Get my GnuPG key from: http://klamath.dyndns.org/mykey.asc Encrypted mail welcomed Good composers borrow. Great composers steal. -- Igor Stravinsky
On Thu, Jan 25, 2001 at 05:14:50PM +0100, Gilles DAROLD wrote: > Hi, > > With Apache/mod_perl it is very simple to enable DB connection > persistance. > > in your perl script : > > use vars qw($dbh); > > $dbh ||= DBI::connect($datasrc, $dbuser, $dbpwd); > > That create a persistance connection to your DB and you do not have to > care > about a pool of connection. Double pipe do all for you :-) > > But if you really want a pool just create an array of this kind of global > var at startup > and switch to any indices as you want. How's that supposed to work? Apache is a multi-process web server. Connection pooling over all Apache children that are currently alive on a web server would require some kind of inter-process communication, which I don't think Apache supports (am I mistaken?). Regards, Frank
On Thu, 25 Jan 2001, Frank Joerdens wrote: > How's that supposed to work? Apache is a multi-process web server. > Connection pooling over all Apache children that are currently alive on > a web server would require some kind of inter-process communication, > which I don't think Apache supports (am I mistaken?). That's what Apache 2.0 is about. It will be able to run in a multi-thread mode, or in multi-process mode with some data shared via shared memory. -alex
On Thu, Jan 25, 2001 at 03:27:21PM -0500, Alex Pilosov wrote: > > On Thu, 25 Jan 2001, Frank Joerdens wrote: > > > How's that supposed to work? Apache is a multi-process web server. > > Connection pooling over all Apache children that are currently alive on > > a web server would require some kind of inter-process communication, > > which I don't think Apache supports (am I mistaken?). > > That's what Apache 2.0 is about. It will be able to run in a multi-thread > mode, or in multi-process mode with some data shared via shared memory. Ah, that explains it. Very cool indeed! Ta, Frank
Take a look to Apache::DBI bye valter >From: Frank Joerdens <frank@joerdens.de> >To: Gilles DAROLD <gilles@darold.net> >CC: pgsql-general <pgsql-general@postgresql.org> >Subject: Re: [GENERAL] Connection pooling >Date: Thu, 25 Jan 2001 20:57:33 +0100 > >On Thu, Jan 25, 2001 at 05:14:50PM +0100, Gilles DAROLD wrote: > > Hi, > > > > With Apache/mod_perl it is very simple to enable DB connection > > persistance. > > > > in your perl script : > > > > use vars qw($dbh); > > > > $dbh ||= DBI::connect($datasrc, $dbuser, $dbpwd); > > > > That create a persistance connection to your DB and you do not have to > > care > > about a pool of connection. Double pipe do all for you :-) > > > > But if you really want a pool just create an array of this kind of >global > > var at startup > > and switch to any indices as you want. > >How's that supposed to work? Apache is a multi-process web server. >Connection pooling over all Apache children that are currently alive on >a web server would require some kind of inter-process communication, >which I don't think Apache supports (am I mistaken?). > >Regards, Frank _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
At 1:40 AM +0100 1/26/01, Valter Mazzola wrote: >Take a look to Apache::DBI > >bye >valter > > >>From: Frank Joerdens <frank@joerdens.de> >>To: Gilles DAROLD <gilles@darold.net> >>CC: pgsql-general <pgsql-general@postgresql.org> >>Subject: Re: [GENERAL] Connection pooling >>Date: Thu, 25 Jan 2001 20:57:33 +0100 >> >>On Thu, Jan 25, 2001 at 05:14:50PM +0100, Gilles DAROLD wrote: >> > Hi, >> > >> > With Apache/mod_perl it is very simple to enable DB connection >> > persistance. >> > >> > in your perl script : >> > >> > use vars qw($dbh); >> > >> > $dbh ||= DBI::connect($datasrc, $dbuser, $dbpwd); >> > >> > That create a persistance connection to your DB and you do not have to >> > care >> > about a pool of connection. Double pipe do all for you :-) >> > >> > But if you really want a pool just create an array of this kind of global >> > var at startup >> > and switch to any indices as you want. >> >>How's that supposed to work? Apache is a multi-process web server. >>Connection pooling over all Apache children that are currently alive on >>a web server would require some kind of inter-process communication, >>which I don't think Apache supports (am I mistaken?). Apache::DBI provides persistent connections within each httpd child process. It does not do connection pooling across httpd children.
Frank Joerdens wrote: > How's that supposed to work? Apache is a multi-process web server. > Connection pooling over all Apache children that are currently alive on > a web server would require some kind of inter-process communication, > which I don't think Apache supports (am I mistaken?). > > Regards, Frank Of course it works, what a strange idea ? When you load a perl script with mod_perl if you define global vars they are defined for all childrens ! Interprocess communication is an other history...
Hi, Just to repeat that we have this stuff enabled using perl and mod_perl for a very long time. Just try to declare all your vars as global (without my or local) and see what's append between apache child process :-) But as I know Apache::DBI doesn't do db connexion pooling, this is a mistake. It just allows you to create persitante connexion. But you can declare multiple persistante connection and do a random access to each one if your really need to play with that. Personnaly I never had to use that, but I think that with a site with a large amout of simoultaneous user it can be usefull. Regards Alex Pilosov wrote: > On Thu, 25 Jan 2001, Frank Joerdens wrote: > > > How's that supposed to work? Apache is a multi-process web server. > > Connection pooling over all Apache children that are currently alive on > > a web server would require some kind of inter-process communication, > > which I don't think Apache supports (am I mistaken?). > > That's what Apache 2.0 is about. It will be able to run in a multi-thread > mode, or in multi-process mode with some data shared via shared memory. > > -alex
At 12:39 PM +0100 1/26/01, Gilles DAROLD wrote: >Hi, > >Just to repeat that we have this stuff enabled using perl and mod_perl for a >very >long time. Just try to declare all your vars as global (without my or local) >and >see what's append between apache child process :-) > >But as I know Apache::DBI doesn't do db connexion pooling, this is a >mistake. >It just allows you to create persitante connexion. But you can declare >multiple >persistante connection and do a random access to each one if your really >need >to play with that. Personnaly I never had to use that, but I think that with >a site >with a large amout of simoultaneous user it can be usefull. The point is that if two child processes share a connection (which is actually just a TCP or Unix socket) then you have two writers to the same output channel. This is a no-no, since data corruption can result, just as if two writers share an open filehandle for writing. It would in theory be possible for somebody to write a connection pool package for Apache that included proper concurrency control. However Apache::DBI doesn't do that. Steve L